Rock quality designation (RQD): time to rest in peace

2017 ◽  
Vol 54 (6) ◽  
pp. 825-834 ◽  
Author(s):  
P.J. Pells ◽  
Z.T. Bieniawski ◽  
S.R. Hencher ◽  
S.E. Pells
Keyword(s):  
Rock Mass ◽  
Classification Systems ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Quality Designation ◽  
Strength Index ◽  
Rock Quality ◽  
Rock Formations ◽  
The Look ◽  
Definition Of

Rock quality designation (RQD) was introduced by Don Deere in the mid-1960s as a means of using diamond core to classify rock for engineering purposes. Subsequently, it was incorporated into the rock mass rating (RMR) and Q-system classification methods that, worldwide, now play substantial roles in rock mechanics design, whether for tunnels, foundations, rock slopes or rock excavation. It is shown that a key facet of the definition of RQD is ignored in many parts of the world, and it is noted that there are several inherent limitations to the use of RQD. Based on mapping of rock formations by 17 independent professionals at different locations in Australia and South Africa, it is shown that differences in assessed RQD values result in significant errors in computed RMR and Q ratings, and also in geological strength index (GSI) and mining rock mass rating (MRMR). The introduction of a look-up chart for assessing GSI has effectively removed the need to measure, or estimate, RQD. It has been found that GSI values derived from the look-up chart are as valid as those derived by calculation from the original component parameters, and are satisfactorily consistent between professionals from diverse backgrounds. The look-up charts provide a quick and appropriate means of assessing GSI from exposures. GSI is, in turn, a useful rock mass strength index; one new application is presented for assessing potential erosion of unlined spillways in rock. Incorporation of RQD within the RMR and Q classification systems was a matter of historical development, and its incorporation into rock mass classifications is no longer necessary.

scholarly journals APPLICABILITY OF THE ROCK MASS RATING (RMR) SYSTEM FOR THE TRUSMADI FORMATION AT SABAH, MALAYSIA

2020 ◽  
Vol 4 (2) ◽  
pp. 96-102
Author(s):  
Rodeano Roslee ◽  
Jeffery Anak Pirah ◽  
Mohd Fauzi Zikiri ◽  
Ahmad Nazrul Madri
Keyword(s):  
Rock Mass ◽  
Classification Systems ◽  
Wire Mesh ◽  
Low Grade ◽  
Rock Mass Rating ◽  
Class Iii ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
Rock Structure ◽  
Class Iv

Rock Mass Classification Systems (RMCS) can be of considerable use in the initial stage of a project when little or no detailed information is available. There is a large number of RMCS developed for general purposes but also for specific applications such as Rock Quality Designation (RQD), Rock Mass Rating (RMR), Rock Structure Rating (RSR), Geological Strength Index (GSI), Slope Mass Rating (SMR), etc. In this paper, we present the results of the applicability of the Rock Mass Rating (RMR) System for the Trusmadi Formation in Sabah, Malaysia. The RMR system is a RMCS incorporated with five (5) parameters: Strength of intact rock material, Rock Quality Designation (RQD), Spacing of joints, Condition of joints, and Groundwater conditions. A total of ten (10) locations were selected on the basis of exposures of the lithology and slope condition of the Trusmadi Formation. Trusmadi Formation is Paleocene to Eocene in aged. The Trusmadi Formation generally shows two major structural orientations NW-SE and NE-SW. Trusmadi Formation is characterized by the present of dark colour argillaceous rocks, siltstone and thin-bedded turbidite in well-stratified sequence. Some of the Trusmadi Formation rocks have been metamorphosed to low grade of the greenish-schist facies; the sediment has become slate, phyllite and metarenite. Cataclastic rocks are widespread and occur as black phyllonite enclosing arenitic and lutitic boudins with diameter up to a meter or demarcating thin to thicker fault zones or as flaser zones with hardly any finer grain matrix or as zones of closely spaced fractures. Quartz and calcite veins are quite widespread within the crack deformed on sandstone beds. The shale is dark grey when fresh but changes light grey to brownish when weathered. The RMR system for 10 outcrops ranges from 33.0 to 50.0 and its classified as “Fair” (Class III) to “Poor” (Class IV) rocks. The Fair Rock (Class III) recommended that the excavation should be top heading and bench 1.5 m – 3 m advance in the top heading. Support should be commencing after each blast and complete support 10 m from face. Rock bolts should be systematic with 4 m long spaced 1.5 m – 2 m in crown and walls with wire mesh in crown. Shotcrete should be 50 mm – 100 mm in crown and 30 mm in sides. While for the Poor Rock (Class IV), the excavation should be top heading and bench 1.0 m – 1.5 m advance in top heading. Support should be installed concurrently with excavation, 10 m from face. Rock bolt should be systematic with 4 m – 5 m long, spaced 1.5 m – 1.5 m in crown and walls with wire mesh. Shotcrete of 100 m – 150 mm in crown and 100 mm in sides. The steel sets should be light to medium ribs spaced 1.5 m only when required.

scholarly journals Correlation of P-wave Velocity with Rock Quality Designation (RQD) in Volcanic Rocks

2019 ◽  
Vol 3 (2) ◽  
pp. 11
Author(s):  
Ainul Fatayaatis Salaamah ◽  
Teuku Faisal Fathani ◽  
Wahyu Wilopo
Keyword(s):  
Rock Mass ◽  
Wave Velocity ◽  
Volcanic Rocks ◽  
Rock Mass Classification ◽  
Classification Systems ◽  
P Wave ◽  
Rock Quality Designation ◽  
Rock Quality ◽  
P Wave Velocity ◽  
Mass Classification

One important part of rock mass investigation is the geomechanical assessment in terms of rock mass classification systems. Rock mass classification is one of themost efficient methods in rock mechanics to provide a basic understanding of rock masscharacterization. Rock mass properties can be determined by a seismic refraction surveyas an indirect geophysical assessment. In this study, the P-wave velocity from seismicrefraction was compared with the Rock Quality Designation (RQD) from the boreholes.The empirical correlation between the RQD and the P-wave velocity was found by usingthe linear regression analysis. The RQD value estimated from the P-wave velocity can beapplied for tropical environment study with geological conditions of volcanic rocks. This study helps to estimate and predict the subsurface rock quality, to reduce investigation costs, and to improve understanding of subsurface rock quality.

Анализ инженерных свойств горных пород участка плотины Шах-и-Арус, Кабул, Афгани

2020 ◽  
Vol 5 (1) ◽  
pp. 35-48
Author(s):  
Абдулхалим Зарьяб ◽  
◽  
Мохаммад Ибрагим Наджаф ◽  
Мохаммад Зия Джамал
Keyword(s):  
Rock Mass ◽  
Rock Mass Rating ◽  
Rock Quality Designation ◽  
Rock Quality

В настоящее время на реке Шакардара примерно в 22 км к северо-западу от г. Кабул, Афганистан, ведется строительство плотины Шах-и-Арус. Ее высота и длина составляют 77,5 м и 303 м, соответственно, а объем водохранилища оценивается примерно в 9,38 млн м 3 . Данное многоцелевое сооружение возводится из роликового уплотненного бетона (RCC) и предназначено для хранения оросительной воды, сдерживания наводнений и выработки электроэнергии. Плотина располагается в тектонически активной зоне, чем обусловливается значительное воздействие на нее тектонических процессов. В настоящей статье представлены результаты сопоставления показателей нарушенности горных пород (Rock Quality Designation, RQD) и параметров Люжона, основанных на обзоре и анализе материалов первоначальных инженерно-геологических изысканий и дополнительных полевых наблюдений. Результаты значений Люжона и показателей RQD прошли статистически-графическую оценку, и далее данные полученных графиков были сопоставлены со всеми другими естественными условиями зоны строительства плотины. Полученные результаты указывают на то, что комплекс природных условий в определенной степени характеризуется взаимосвязью между значениями Люжона и параметрами RQD. Кроме этого, массив горных пород основания плотины был охарактеризован в соответствии с классификацией скальной породы RMR (Rock Mass Rating).

scholarly journals Rock Mass Rating and Geological Strength Index of rock masses of Thopal-Malekhu River areas, Central Nepal Lesser Himalaya

2013 ◽  
Vol 16 ◽  
pp. 29-42 ◽  
Author(s):  
Jaya Laxmi Singh ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Rock Mass ◽  
Surface Condition ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Slopes ◽  
Lesser Himalaya ◽  
Rock Masses ◽  
Strength Index ◽  
Rock Mass Structure ◽  
Exposed Rock

The rock slopes of the Thopal-Malekhu River areas, Lesser Himalaya, were characterized applying various systems of rock mass classification, such as Rock mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well exposed rock formations of the Nawakot and Kathmandu Complexes, across the Thopal-Malekhu River areas. In RMR system, mainly five parameters viz. Uniaxial Compressive Strength (UCS) of rock, Rock Quality Designation (RQD), spacing of discontinuity, condition of discontinuity, and groundwater condition were considered. The new GSI charts, which were suitable for schistose and much disintegrated rock masses, were used to characterize rock slopes based on quantitative analysis of the rock mass structure and surface condition of discontinuities. RMR ranged from 36 to 82 (poor to very good rock mass) and GSI from 13.5±3 to 58±3 (poor to good rock mass). Slates (of the Benighat Slate) are poor rock masses with low strength, very poor RQD, and close to very close spacing of discontinuity, and dolomites (Dhading Dolomite) are fair rocks with disintegrated, poorly interlocked, and heavily broken rock masses yielding very low RMR and GSI values. Phyllites (Dandagaun Phyllite), schist (Robang Formation) and quartzite (Fagfog Quartzite, Robang Formation and Chisapani Quartzite), dolomite (Malekhu Limestone), and metasandstone (Tistung Formation) are fair rock masses with moderate GSI and RMR values, whereas quartzose schist and gneiss (Kulekhani Formation) are very good rock masses having comparatively higher RMR and GSI. The relationship between GSI and RMR shows positive and good degree of correlation. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8882   Bulletin of the Department of Geology Vol. 16, 2013, pp. 29-42

GEOMETRI PELEDAKAN BERDASARKAN ROCK MASS RATING (RMR) DAN FRAGMENTASI HASIL PELEDAKAN

2020 ◽  
Vol 4 (4) ◽  
pp. 209-215
Author(s):  
Aprilliana ◽  
Taufik Toha ◽  
Budhi Kuswan Susilo
Keyword(s):  
Rock Mass ◽  
Rock Mass Rating ◽  
Rock Quality Designation ◽  
Rock Quality

Peledakan merupakan salah satu metode pembongkaran lapisan batuan. Hasil dari peledakan ini adalah fragmentasi batuan yang berukuran beragam. Salah satu faktor yang mempengaruhi ukuran fragmentasi ini sangat dipengaruhi oleh geometri peledakan. Geometri peledakan sulit untuk dievaluasi karena belum pernah melakukan analisis fragmentasi hasil peledakan menggunakan software. Tujuan dari penelitian ini adalah mengevaluasi geometri peledakan, Identifikasi kelas massa batuan menggunakan Rock Mass Rating (RMR), dan menganalisis fragmentasi hasil peledakan. Metode identifikasi kelas massa batuan dalam penelitian ini menggunakan metode rock mass rating (RMR) meliputi kuat tekan batuan, rock quality designation (RQD), jarak diskontinuity, kondisi diskontinuity, dan air tanah. Sedangkan fragmentasi hasil peledakan dianalisis menggunakan software split desktop. Pada analisis ini foto fragmentasi hasil peledakan di front dan di disposal diambil langsung sebagai data utama yang menjadi dasar dari analisis ini. Berdasarkan hasil analisis RMR diketahui bahwa batuan yang dibongkar adalah jenis claystone dengan rating kuat tekan 1, RQD 8, Jarak diskontinuitas 15, kondisi diskontinuitas 0, kondisi air tanah 15. Jadi total rating RMR 39 yang berarti batuan ini tergolong batuan jelek atau lunak. data diketahui bahwa batuan yang diledakkan merupakan jenis claystone kelas IV yang berarti jelek atau lunak, Hasil analisis fragmentasi hasil peledakan di disposal lebih kecil dan seragam dibandingkan dengan fragmentasi di front, perbedaan ukuran fragmentasi ini akibat adanya pengaruh dari aktivitas gali muat dan angkut material dari front ke disposal. Produktivitas excavator sudah sesuai dengan buku panduan yang berarti fragmentasi hasil peledakan sudah baik sehingga geometri peledakan tidak perlu diperbaiki.

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